2628 02 What is Subsea

November 2012

Introduction to Subsea Production Systems

02 What is “Subsea”?

© Det Norske Veritas AS. All rights reserved.November 2012

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What is “Subsea”?


What is Subsea?

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Subsea example


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Subsea example


History of Subsea Technology 1943 – First subsea completion (Lake Erie, USA, 30 feet)

1961 – First subsea well completed in Gulf of Mexico by Shell (50 feet)

1967 – First diverless subsea completion

1971 – First North Sea Subsea development, Ekofisk early production (220 feet)

1973 – First multiwell subsea template

1978 – 140 operational subsea wells worldwide 1992 – First horizontal Xmas tree

1997 – 1000 subsea wells completed worldwide 2003 – Shell Penguins (North Sea), 65 km, longest subsea oil tie-back

2004 – 2400 subsea wells completed worldwide 2007 – Statoil Snøhvit (Barents Sea), 143 km, longest subsea gas tie-back

2008 –3000 subsea wells completed worldwide 2010 –4000 subsea wells completed worldwide 2010 – Shell Perdido (GoM), 2934 m water depth, deepest subsea field

2012 –5000 subsea wells completed worldwide

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Why Subsea Wells?


Why Subsea Wells? Subsea wells can be placed outside the effective drilling reach of existing platforms

Subsea wells can usually be installed faster than the construction time for a platform

If surface facilities are available, an expensive platform (Spar, semi sub or TLP) can be avoided

A less expensive platform can be installed if flowlines from subsea wells rather than casing riser are tied back to the surface (reduced platform load)

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Subsea Wells Challenges Flow assurance problems can be costly.

- Hydrates, Paraffin/Wax, Asphaltenes, Sand, Scale, Corrosion, Multiphase Flow (water injection and gas wells have less problems)

Subsea wells cost more to drill, complete and workover - Rig spread cost is higher and more time per well

Operating costs are higher per well than for dry tree wells

Less reserves are recovered before reaching economic limit

Compared to dry wellheads, the access to a subsea well is expensive, making workover less available

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Subsea Development Concepts

Moored SemiTie-back to Shore


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Standards, Rules and RegulationsSafety Considerations, Subsea Production Systems

NPD “Innretningsforskriften” referring NORSOK D-010

Barrier Philosophy, mandatory requirements:

During drilling and well activities at least two independent and tested barriers shall be available in order to prevent unintentional flow from well

If one of the barriers fail, immediate measures shall be taken to re-establish two barriers

It shall be possible to test the barriers. To the extent possible the barriers shall be tested in the direction of flow


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Standards, Rules and Regulations

Frame agreement specifications

ProjectDesign Basis

Auth.Rules & Reg.

Relevant NORSOK, ISO and API standards

Operation & Maint. Req's

Functional and Design Req's

Authorities

Operator

Standards


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ISO 13628 series


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References… ISO 10423/API 6A Recommended Practice for Design & Operation of Subsea Production Systems ISO 13628-4/API 17D Specification for Subsea Wellhead and Christmas Tree Equipment US Coastguard and Minerals Management Service (MMS) rules and regulations ISO 10423/API 6A, Specification for Valves, Wellhead and Christmas Tree Equipment ISO 13628-1 to 9, Design and Operation of Subsea Production Systems DNV, Rules for Planning and Execution of Marine Operations NORSOK U-001 Subsea Production Systems - Norwegian Codes UKOOA – UK Offshore Operators Association AUS – Australian Codes CAN – Canadian Codes ASME, ASTM, AWS, NACE . . . . IEC 61508 / 61511 – Functional safety of electrical/electronic/programmable electronic safety related systems OLF 066 & 070 – Recommended guidelines for the application of IEC 61511 in petroleum activity on Norwegian Continental Shelf


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The Oilfield Glossary

Schlumberger web site:

http://www.glossary.oilfield.slb.com/

POSC Caesar web site:

http://www.posccaesar.com/

http://www.glossary.oilfield.slb.com/

http://www.posccaesar.com/


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Abbreviations…


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Safeguarding life, property and the environment

www.dnv.com

Documents

2628 02 What is Subsea